The sky’s the limit with the new Cadillac Ciel concept car — or so it might seem with the striking convertible that hints at the future flagship model under development at the General Motors luxury brand.

It’s been a tough few years for Cadillac, but the once-dominant car brand is intent on regaining the momentum it seemed to have a decade ago. That's when it first introduced the edgy, “Art & Science” design theme meant to differentiate the brand from other luxury nameplates that often have had a tendency to look a bit too much alike.

While the Ciel — which means “sky” in French — has not yet received formal approval, company insiders like GM global design director Ed Welburn are pushing for the prototype, which would position Caddy head-to-head against the best cars offered by luxury segment leaders Lexus, BMW and Mercedes-Benz.

Meanwhile, GM management has already given the go-ahead to a variety of other new Cadillac models that they hope will broaden the brand’s appeal.

“You need a flagship in your portfolio to be successful in the luxury market today,” said Clay Dean, Cadillac’s lead designer.

The Ciel is a hint of what such a car might be. Nearly as long as the big Escalade sport-utility vehicle, the prototype shown in convertible form at last week’s Pebble Beach Concours d’Elegance would likely undergo a number of changes before hitting showrooms. It may first launch in sedan form.

Although the concept offers what Welburn called “a hint of a fin,” Dean’s goal was not to go retro but take the edgy Art & Science theme even more into the future.

The original CTS sedan introduced the styling concept and delivered the first significant bump in demand for the brand in decades. But subsequent products — such as the bigger STS sedan and XLR roadster, which was Caddy’s answer to the classic Mercedes-Benz SL — landed with a thud, leading many to question whether the CTS was a one-shot wonder.

The latest version of that midsize model has again generated good reviews and buyer enthusiasm, and so has a more stylish remake of the SRX crossover. But two strong products can’t carry a brand in today’s luxury market, analysts caution, especially since Cadillac’s lead rivals are undergoing massive product proliferation.

Consider Mercedes. Two decades ago the automaker debated whether to add the small C-Class to its line-up, which then consisted of the mid-luxury E-Class, the big S-Class and the SL roadster. Today, the automaker’s line-up includes the even smaller A- and B-Class offerings, the GLK, the G- and M-Class crossovers, the V-Class van and a long list of sedans and coupes.

“I think they’ve acknowledged they’ve fallen behind,” said Dave Sullivan, an automotive analyst at AutoPacific, referring to Cadillac. “They’re no longer the ‘standard of the world,’ as they’ve long liked to proclaim.”

It’s not that the Detroit brand doesn’t want to regain that image, and new products will be critical to reclaiming the high ground. Alongside the second-generation CTS sedan, Cadillac has added a striking new coupe version, a station wagon and super-high-performance V-Series versions.

Other new vehicles are in the works. Last week, GM officials confirmed they had reversed a previous decision and will now bring the well-reviewed Converj concept to market. The production version of the plug-in hybrid — which will share a powertrain with the mainstream Chevrolet Volt — will be dubbed the ELR.

GM will also add a new small car, tentatively called the ATS, and a replacement for the much-maligned STS that is expected to be marketed as the XTS.

The next CTS, meanwhile, will become slightly larger and more luxurious, taking on products like the BMW 5-Series and Mercedes.

A decision on whether to add Ciel is likely by year’s end, according to Cadillac sources. It would likely take another three years to bring to market what is being referred to internally as the “Omega” vehicle. Few expect to see the over-the-top design of the Ciel — which would be the first production four-door convertible in half a century — but the styling theme, with its signature Cadillac grille, would clearly influence the final product.

Significantly, several company officials stressed that the Omega project is being heavily influenced by potential demand in emerging markets, particularly China, where luxury cars are in high demand. Indeed, that has helped usher in an unlikely turnaround for Caddy’s sibling brand, Buick, which is one of the best-sellers in the booming Asian nation.

Chinese buyers have proved surprisingly picky, in part because many luxury car owners prefer to be chauffeured, so they want plenty of rear seat room and amenities. The CTS was upgraded for Chinese dealers — much as the latest Buick flagship, the Lacrosse, was largely developed to meet the more expansive demands of China’s buyers.

Cadillac has struggled to get into foreign markets in recent decades, particularly Europe, so analyst Sullivan warns “it won’t be easy” to break out of North America in the future. But with a broader array of products, Cadillac officials are hoping they will be better positioned to stand up to the rivals wherever they compete, whether in the home U.S. market, Europe or the new markets that are rapidly becoming the place to be for luxury brands.

The hatchback’s comeback

By Paul A. Eisenstein ,
msnbc.com contributor

American motorists are often described as fixed in their ways and unwilling to try new things, yet there are signs that this might not hold true anymore. There are signs car buyers are open to alternative body designs that can enhance both form and functionality, especially as more and more motorists downsize to reduce fuel costs.

In some cases, that mean old ideas are making a comeback – the hatchback, for example.

Take Audi's A7.

After years as an also-ran in the global luxury car market, Audi has been steadily gaining ground on its leading challengers, Germany’s Mercedes-Benz and BMW, as well as Japan’s Lexus – and its reputation for striking design is a major reason.

The A7 is Audi’s latest hit. It’s a coupe-like sedan or, more accurately, a coupe-like hatchback. Five-door designs are wildly popular in Europe and many other parts of the world but have long been anathema to American motorists.
(AP)
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Ford Fiesta

While some carmakers are still reluctant to bring hatchback designs to the U.S. market, Ford is betting big on 5-door models like the Fiesta subcompact, shown here, and the new Focus compact.

Demand for hatchbacks in the U.S. small car segment has surged from 15.5 percent in 2003 to 41.8 percent last year. Overall hatchback sales, meanwhile, shot up 63 percent between 2006 and 2010, to 475,048.
(Ford / AP)
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Chevrolet Corvette

Would a rose by any other name smell so sweet?

The Bard’s words might as well be applied to products like the Chevrolet Corvette. Sure, most motorists are likely to call it a sports car, but take a closer look and you’ll realize the ‘Vette has traditionally gone for a hatchback design – as have many of the most popular classic sports cars.
(Gm / Wieck)
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Jeep Grand Cherokee

What is the SUV if not a hatchback (unless you prefer to call it a station wagon on steroids)? Ironically, it’s the big rear hatch that gives so much flexibility to the conventional sport-utility vehicle, as well as its more fuel-efficient cousin, the crossover vehicle. Count them and hatchback sales suddenly rival those of the sedan.
(Stan Honda / AFP/Getty Images)
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Mini Cooper

The Mini Cooper is another European take on the hatchback. The iconic small-car brand has shown that both small cars and 3-door designs can click with the American motoring public. Mini will soon offer a total of seven hatch-based designs in the U.S. market.
(Mini)
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BMW X6

BMW’s unusual X6 is a hatchback blend of conventional SUV and sports car. The muscular design has had a significant influence on both luxury and mainstream automakers over the last several years – even though it is more an exercise in form than functionality.
(Tom Kirkpatrick / eb.andriuolo/BMW)
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Honda Crosstour

Among those who have echoed the X6 design are Honda and its up-market sibling, Acura.

The mainstream brand has struggled with the Accord Crosstour and hopes to pump new life into the design by adding more features and simplifying the name to just Honda Crosstour for 2012.

The Acura ZDX isn’t doing much better in the market and both may not last much beyond the 2012 model-year – which could extend the myth that Americans won’t buy hatchbacks.
(Honda)
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Ford Pinto

The Ford Pinto is one reason why hatchbacks lost their luster in the U.S. market. The once-popular subcompact was a mainstay of the 1970s but, like so many hatchbacks of the era, it offered little in the way of creature comforts and other amenities. Making matters worse was the Pinto’s flawed gas tank design, associated with a number of deadly fires.
(Ford / Wieck)
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Chevrolet Vega

The Chevrolet Vega was another reason why hatchbacks lost their appeal in the U.S.

AMC Gremlin

Few carmakers were more committed to the hatchback than American Motors.

It offered a wide variety of alternatives -- especially considering the size of the company. The Gremlin, shown here, was among its most popular hatch models, along with the Alliance, marketed under the brand of one-time French ally Renault.

But one of the most curious AMC offerings was the Pacer, originally designed to use the radical Wankel rotary, though converted to a conventional engine due to quality and mileage problems with the rotary.
(Hulton Archive / Getty Images)
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Editor's note:
This image contains graphic content that some viewers may find disturbing.

In a highly-anticipated speech to Congress Tuesday, Israeli Prime Minister Benjamin Netanyahu argued that a potential nuclear deal being negotiated by major powers including the United States "paves Iran's path to the bomb."